This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
In downhole drilling, the drilling elements comprising a drilling tool are frequently coupled together by threaded structures. In these coupled drilling elements, the thread design is critical since failure often occurs in the thread structure. Whenever fatigue induced failure in the thread structure does occur, the initial crack starts at the thread root. This is due to the high stress concentrations located at the root of the threads when the thread structure is subject to severe loading.